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Search results for: HARMONIC COMPENSATION
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Harmony Search to Self-Configuration of Fault-Tolerant Grids for Big Data
PublicationIn this paper, harmony search algorithms have been proposed to self-configuration of fault-tolerant grids for big data processing. Some tasks related to big data processing have been considered. Moreover, two criteria have been applied to evaluate quality of grids. The first criterion is a probability that all tasks meet their deadlines and the second one is grid reliability. Furthermore, some intelligent agents based on harmony...
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Analytical model with non-adiabatic effects for pressure drop and heat transfer during boiling and condensation flows in conventional channels and minichannels
PublicationIn the paper a method developed earlier by authors is applied to calculations of pressure drop and heat transfer coefficient for boiling flow and condensation flow with account of non- adiabatic effects for some recent data collected from literature. The first effect, the modification of interface shear stresses in annular flow pattern is considered through incorporation of the so called "blowing parameter". The mechanism of...
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Challenges in QCD matter physics --The scientific programme of the Compressed Baryonic Matter experiment at FAIR
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Anharmonic Infrared Spectroscopy through the Fourier Transform of Time Correlation Function Formalism in ONETEP
PublicationDensity functional theory molecular dynamics (DFT-MD) provides an efficient framework for accurately computing several types of spectra. The major benefit of DFTMD approaches lies in the ability to naturally take into account the effects of temperature and anharmonicity, without having to introduce any ad hoc or a posteriori corrections. Consequently, computational spectroscopy based on DFT-MD approaches plays a pivotal role in...
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Towards Gender Harmony Dataset: Gender Beliefs and Gender Stereotypes in 62 Countries
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A tetragonal polymorph of SrMn2P2 made under high pressure – theory and experiment in harmony
PublicationFollowing the predictions of total energy calculations, a tetragonal SrMn2P2 phase is proposed and successfully formed under high pressure. At ambient pressure, SrMn2P2 adopts the primitive trigonal La2O3 structure type (space group P[3 with combining macron]m1). However, the results of total energy calculations indicate that SrMn2P2 should be more stable in the tetragonal ThCr2Si2 structure type (space group I4/mmm) than in its...
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Application of Feed Forward Neural Networks for Modeling of Heat Transfer Coefficient During Flow Condensation for Low and High Values of Saturation Temperatur
PublicationMost of the literature models for condensation heat transfer prediction are based on specific experimental parameters and are not general in nature for applications to fluids and non-experimental thermodynamic conditions. Nearly all correlations are created to predict data in normal HVAC conditions below 40°C. High temperature heat pumps operate at much higher parameters. This paper aims to create a general model for the calculation...
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Response to the queries raised by Dr M.M. Awad in a letter to editor comments on “Pressure drop of HFE7000 and HFE7100 during flow condensation in minichannels”
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The level of jasmonic acid in Arabidopsis thaliana and Phaseolus coccineus plants under heavy metal stress
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Corrosion behaviour of low carbon steel in artificial seawater using TP, LP, EIS, Harmonic Analysis (HA) and new method Dynamic Electrochemical Impedance Spectroscopy (DEIS)
PublicationZe względu na istotną rolę technik elektrochemicznych w badaniach procesów korozyjnych są one szeroko stosowane w monitorowaniu korozji. Celem niniejszej pracy jest zgromadzenie rezultatów wyników doświadczalnych uzyskanych różnymi technikami i znalezienie korelacji między nimi. Własności korozyjne stali stopowej (AISI 1026) w sztucznej wodzie morskiej zostały zbadane z wykorzystaniem ekstrapolacji tafelowskiej (TP), polaryzacji...
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Extraction pathways and purification strategies towards carminic acid as natural-based food colorant: A comprehensive review
PublicationAs a current trend of fabricating healthier products, food manufacturing companies seek for natural-based food colorant aiming to replace the synthetic ones, which apart from meeting sensorial and organoleptic aspects, they can also act as health promoters offering additional added value. Carminic acid is a natural based food colorant typically found in several insect taxa. However, there are current approaches which pursue the...
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Badania teoretyczne rozkładu pola ciśnienia anteny wieloelementowej. Teoretical investigations of the pressure distribution for biharmonic transmitting array.
PublicationOmówiono zagadnienie oddziaływań fal dla hydroakustycznej anteny wieloelementowej bez osiowej symetrii. Przedstawiono model matematyczny i wyniki badań teoretycznych. Rozpatrzono dwie konfiguracje anteny. Model matematyczny zbudowano w oparciu o równanie KZK.
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СИЛОВОЙ ПРЕОБРАЗОВАТЕЛЬ С АКТИВНЫМ ПОДАВЛЕНИЕМ ВЫСШИХ ГАРМОНИК ДЛЯ СИСТЕМ ЭЛЕКТРОСНАБЖЕНИЯ ЛЕТАТЕЛЬНЫХ АППАРАТОВ (Power converter with active suppression of higher harmonics for aircraft power supply systems)
PublicationПредставлены два алгоритма активной фильтрации для силового преобразователя с активным подавлением высших гармоник. Первый алгоритм основан на дискретном преобразовании Фурье: посредством синтезированной системы управления инвертированные измеренные высшие гармоники напряжения поступают на вход инвертора. Второй метод управления основан на алгоритме с использованием принципов самообучения, что значительно снижает потребность в...
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Investigation of an elutable N-propylphosphonic acid chitosan derivative composition with a chitosan matrix prepared from carbonic acid solution
PublicationPorous chitosan composites using CO2 dissolution procedure and including water soluble N-propylphosphonic chitosan derivative (p-CHI) were obtained and characterized. In contrast to the control material, composites containing modified chitosan distinguished by a rapid moisture absorption and good adhesion to the skin. The FTIR analysis confirmed the presence of propylphosphonic group in the structure of the polymer. The porosity...
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Standards for Quality Assurance in the European Higher Education Area versus Common Assessment Framework in education. Conflict or harmony?
PublicationThe aim of the research was to analyze the assumptions of Standards and Guidelines for Quality Assurance in the European Higher Education Area (ENQA) and the criteria of Common Assessment Framework (CAF) for the educational sector and based on that to find out the main differences and similarities (conflicts and harmony) between them. The results of the research showed that the current trends of the quality movement evolution in...
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Measurement system for nonlinear surface spectroscopy by atomic force microscopy for corrosion processes monitoring
PublicationIn addition to traditional imaging the surface, atomic force microscopy (AFM) enables wide variety of additional measurements. One of them is higher harmonic imaging. In tapping mode the nonlinear contact between tip and specimen results in higher frequency vibrations. More information available from the higher harmonics analysis proves to be helpful for more detailed imaging. Such visualization is especially useful for heterogeneous...
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Laser stimulated third harmonic generation studies in ZnO–Ta 2 O 5 –B 2 O 3 glass ceramics entrenched with Zn 3 Ta 2 O 8 crystal phases
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Insulin-like growth factor type 2 is better than insulin-like growth factor type 1 a survival marker in patients after acute decompensation of heart failure
PublicationIntroduction:A decreased IGF-1 has been found in heart failure (HF). There are no reports assessing IGF-2 in HF, although in vitro study has shown, that IGF-2 stimulates cardiomyocyte proliferation more than IGF-1. The study aim was to compare the IGF-1 and IGF-2 concentration depending on HF exacerbation and annual survival.Material and methods:Among 75 patients hospitalized...
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A measurement system for nonlinear surface spectroscopy with an atomic force microscope during corrosion process monitoring
PublicationIn addition to traditional imaging the surface, atomic force microscopy (AFM) enables wide variety of additional measurements. One of them is higher harmonic imaging. In tapping mode the nonlinear contact between tip and specimen results in higher frequency vibrations. More information available from the higher harmonics analysis proves to be helpful for more detailed imaging. Such visualization is espe-cially useful for heterogeneous...
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A robust 18-pulse diode rectifier with coupled reactors
PublicationThe article presents the principle of operation and selected results of simulation and laboratory tests of the 18-pulse rectifier system with coupled reactors and small series active power filter. The presented system makes it possible to reduce, especially in distribution supply networks, undesired higher current harmonics. The 18-pulse nature of operation of the rectifier is reached using a set of coupled three-phase network...
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Open-Phase Fault Detection Method for Sensorless Five-Phase Induction Motor Drives with an Inverter Output Filter
PublicationThe paper presents the sensorless five-phase induction motor drive implementation with an inverter output filter with third harmonic injection. For the sensorless operation, the required observers are presented for the first and third harmonics with consideration of the inverter output filter. Moreover, the interaction of the observers and the control system is capable to handle a deactivation of one or two phases, which improves...
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Metodyka badań rozwojowych nowego typu silników i pomp satelitowych
PublicationResearch and development of new type satellite motors and satellite pumps SM with small geometrical displacement, from 5 to 73 cm3/rev, has been conducted in cooperation with Stosowanie Maszyn company from Katowice (manufacturer of motors and pump SM). The improvement of construction of those machines, especially construction of axial compensation and construction of fluid distribution channels have been the main problem of research...
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Formowanie wektorów napięcia wyjściowego w pięciofazowych falownikach napięcia
PublicationW falownikach pięciofazowych, załączenie wektorów aktywnych powoduje jednoczesne formowane dwóch, zależnych od siebie wektorów napięcia wyjściowego. Sterowanie pięciofazowymi silnikami indukcyjnymi wymaga, aby wektory te miały ściśle określone długości i położenia. Niezależne formowanie dwóch wektorów napięcia o parametrach określonych w układzie sterowania silnikiem wymaga zastosowania odpowiedniej strategii Modulacji Szerokości...
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The Reception of the Copernican Universe by Representatives of 17th-Century Jewish Philosophy and Their Search for Harmony Between the Scientific and Religious Images of the World (David Gans and Joseph Solomon Delmedigo)
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A CMOS Pixel With Embedded ADC, Digital CDS and Gain Correction Capability for Massively Parallel Imaging Array
PublicationIn the paper, a CMOS pixel has been proposed for imaging arrays with massively parallel image acquisition and simultaneous compensation of dark signal nonuniformity (DSNU) as well as photoresponse nonuniformity (PRNU). In our solution the pixel contains all necessary functional blocks: a photosensor and an analog-to-digital converter (ADC) with built-in correlated double sampling (CDS) integrated together. It is implemented in...
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Influence of plastic deformation on stray magnetic field distribution of soft magnetic steel sample
PublicationThe effect of various combinations of conditions, i.e., presence of the Earth’s magnetic field during and after deformation on the distribution of stray magnetic field of S355 steel sample, which is locally deformed, was investigated. Some of the stages of the experiment were carried out in zero magnetic field. Compensation of the Earth’s magnetic field was obtained by the application of a pair of Helmholtz coils. These coils are...
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Modeling the effect of parasitic capacitances on the dead-time distortion in multilevel NPC inverters
PublicationA simple model is derived and verified for evaluating the effect of parasitic capacitances on the dead-time related voltage distortion in multilevel NPC voltage source inverters. The model permits well-defined and precise compensation of dead-time distortion, exhibiting meaningful improvement on compensation methods neglecting the effects of parasitic capacitances. A simple formula is given for evaluating the capacitances as serial/parallel...
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WYKORZYSTANIE TESTU MUSHRA W BADANIU KORZYŚCI UŻYTKOWANIA PROTEZ SŁUCHOWYCH
PublicationOcena jakości dopasowania aparatów słuchowych w kontekście korzyści, jakie może przy-nieść proteza jest złożonym zagadnieniem. Obiektywne parametry aparatów, które można wy-znaczyć (np. wzmocnienie czy pasmo przenoszenia) nie zawsze mają bezpośredni i decydujący wpływ w subiektywnej ocenie jakości dopasowania protezy słuchowej przez pacjenta. Pomiary efektywności aparatu słuchowego mogą dotyczyć wielu aspektów, między innymi kompensacji...
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Low Frequency Conducted Emissions of Grid Connected Static Converters
PublicationPulse-width modulated rectifiers are nowadays commonly used for AC to DC power conversion. PWM rectification technology is very effective and allows for bidirectional power flow with the possibility of power factor improvement and low-order harmonic emission limitation. Unfortunately, employed PWM boost topology results with generation of input current harmonic distortions in a frequency range tightly correlated to modulation frequency....
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Failure analysis of a high-speed induction machine driven by a SiC-inverter and operating on a common shaft with a high-speed generator
PublicationDue to ongoing research work, a prototype test rig for testing high-speed motors/generators has been developed. Its design is quite unique as the two high- speed machines share a single shaft with no support bearings between them. A very high maximum operating speed, up to 80,000 rpm, was required. Because of the need to minimise vibration during operation at very high rotational speeds, rolling bearings were used. To eliminate...
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Simulation of fluid structure interaction in a novel design of high pressure axial piston hydraulic pump
PublicationA novel type of an axial, piston-driven high pressure hydraulic pump with variable capacity marks a significant improvement in the area of the hydraulic machinery design. Total discharge from hydrostatic forces eliminates a need for a servomechanism, thus simplifying operation, reducing weight and introducing the possibility of the pump displacement control by computer. PWK-type pumps, invented in the Gdansk University of Technology,...
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Simulation of fluid structure interaction in a novel design of high pressure axial piston pump
PublicationA novel type of an axial, piston-driven high pressure hydraulic pump with variable capacity marks a significant improvement in the area of the hydraulic machinery design. Total discharge from hydrostatic forces eliminates a need for a servomechanism, thus simplifying operation, reducing weight and introducing the possibility of the pump displacement control by computer. PWK-type pumps, invented in the Gdansk University of Technology,...
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Grid-Forming Operation of Energy-Router Based on Model Predictive Control with Improved Dynamic Performance
PublicationThe focus of this study is on the grid-forming operation of the Energy Router (ER) based on Model Predictive Control (MPC). ER is regarded as a key component of microgrids. It is a converter that interfaces the microgrid (s) with the utility grid. The ER has a multiport structure and bidirectional energy flow control. The ER concept can be implemented in Nearly Zero-Energy Buildings (NZEB) to provide flexible energy control. A...
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Modernization of the Trailer for Tyre/Road Rolling Resistance Measurements
PublicationIn the article the ways of defining tyre rolling resistance are presented. The advantages of the laboratory tests of tyre/road rolling resistance and the advantages and disadvantages of on the road tyre/road rolling resistance tests are described. The description of the special trailer used for tyre/road rolling resistance measurements designed and constructed in the Faculty of Mechanical Engineering at Gdansk University of Technology,...
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Electric shock hazard in circuits with variable-speed drives
PublicationThe conventional approach to electrical safety under fault condition in typical power systems considers earth fault currents of sinusoidal waveform and frequency of 50/60 Hz. However, in circuits with variable-speed drives, there is earth fault current flow with harmonics, and these harmonics influence the threshold of ventricular fibrillation. The paper presents earth fault current waveforms in circuits with variable-speed drives...
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Sensorless Control of Induction Motor Based on Super-Twisting Sliding Mode Observer With Speed Convergence Improvement
PublicationThe super twisting sliding-mode observer (ST-SMO) has been proposed to achieve an effective method for alleviating low-order harmonics of measured quantities, issues related to DC drift, and suppression of chattering due to low-frequency sampling. The conventional ST-SMO, on the other hand, suffers from control delay in the convergence trajectory due to the system disturbance, resulting in decreased anti-disturbance capability...
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Fast Real-Time RDFT- and GDFT-Based Direct Fault Diagnosis of Induction Motor Drive
PublicationThis paper presents the theoretical analysis and experimental verification of a direct fault harmonic identification approach in a converter-fed electric drive for automated diagnosis purposes. On the basis of the analytical model of the proposed real-time direct fault diagnosis, the fault-related harmonic component is calculated using recursive DFT (RDFT) and Goertzel DFT (GDFT), applied instead of the full spectrum calculations...
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Controlling the europium oxidation state in diopside through flux concentration
PublicationThis paper explores the connection between the H3BO3 flux concentration and the co-existence of Eu2+ and Eu3+ dopants within CaMgSi2O6 crystals (diopside). The samples were synthesised using a solid-state synthesis method under varying atmospheric conditions, including oxidative (air), neutral (N2), and reductive (H2/N2 mixture) environments. Additionally, some materials underwent chemical modification by partially substituting...
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The Impact of Micro-Sources on Voltage Distortions in a Power Grid
PublicationThe increase in the number of photovoltaic (PV) systems integrated with low voltage (LV) grids has led to a great need to analyse the impact of these systems on the quality of electricity and the reliability of its supply. This paper presents and compares the energy quality requirements imposed by various countries on photovoltaic plants. Then, based on real object tests and simulation in DIgSILENT PowerFactory, the impact has...
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Neutral point balancing technique for 3-level neutral point clamped converter with servo system
PublicationNeutral point voltage drift compensation technique in 3-level NPC multilevel converter and servo system is described in the paper. Analytical expressions are obtained for power subsystem elements parameters of servo drive system. Simulation of servo system, based on PMSM motor with 3-level NPC converter is considered.
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Topography measurement methods evaluation for entire bending-fatigued fracture surfaces of specimens obtained by explosive welding
PublicationIn this paper, the methods of compensation of differences in the results of entire bending-fatigued fracture surface topographies were presented. The roughness evaluation was performed with a focus variation microscope and confocal surface topography measurement techniques. The differences in the ISO 25178 roughness parameters were investigated and procedures for their compensation were studied. It was found that various types...
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Carbonic anhydrase inhibitors. Synthesis, and molecular structure of novel series N-substituted N'-(2-arylmethylthio-4-chloro-5- methylbenzenesulfonyl)guanidines and their inhibition of human cytosolic isozymes I and II and the transmembrane tumor-associated isozymes IX and XII
PublicationA series of novel N-substituted N'-(2-arylmethylthio-4-chloro-5-methylbenzenesulfonyl)guanidines 9 e41 have been synthesized and investigated as inhibitors of four isoforms of zinc enzyme carbonic anhydrase (CA.EC 4.2.1.1), that is the cytosolic CA I and II, and cancer-associated isozymes CA IX and XII. Against the human CA I investigated compounds showed KI in the range of 87e6506 nM, toward hCA II ranging from 7.8 to 4500 nM,...
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Generalized adaptive comb filters/smoothers and their application to the identification of quasi-periodically varying systems and signals
PublicationThe problem of both causal and noncausal identification of linear stochastic systems with quasiharmonically varying parameters is considered. The quasi-harmonic description allows one to model nonsinusoidal quasi-periodic parameter changes. The proposed identification algorithms are called generalized adaptive comb filters/smoothers because in the special signal case they reduce down to adaptive comb algorithms used to enhance...
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Formowanie napięć wyjściowych trójfazowego przekształtnika sieciowego
PublicationW artykule przedstawiono kompensację dwu zasadniczych zjawisk powodujących zniekształcenia prądów fazowych przekształtnika sieciowego. Pierwszym z nich są zniekształcenia napięcia sieci. W celu ich eliminacji zaproponowano uśrednianie za okres podstawowej harmonicznej uchybu regulatora napięcia obwodu pośredniczącego oraz predykcję napięcia sieci. Drugim natomiast są zniekształcenia napięć wyjściowych przekształtnika sieciowego....
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Development of a spray-ejector condenser for the use in a negative CO2 emission gas power plant
PublicationOne promising solution for developing low-emission power technologies is using gaseous fuel combustion in pure oxygen when the exhaust gas mixture is composed of H2O and CO2, and where CO2 is separated after steam condensation. The paper presents the results of computational analyses providing to the Spray-Ejector Condenser (SEC) development, which is one of the crucial components of the negative CO2 gas power plant (nCO2PP) cycle...
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SVC and power transformers controllers coordination
PublicationThe use of shunt compensators such as FACTS (for example SVC) in power systems gives possibility of fast and flexible control of voltage or reactive power. An efficient cooperation between a transformer and compensator connected to busbars, or transformer’s tertiary winding, requires a proper coordination of controls. The article contains theoretical considerations and simulation results which indicate that such co-ordination is...
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Sensorless Multiscalar Control of Five-Phase Induction Machine with Inverter Output Filter
PublicationThe paper presents a complete solution for speed sensorless control system for five-phase induction motor with voltage inverter, LC filter and nonlinear control of combined fundamental and third harmonic flux distribution. The control principle, also known as multiscalar control, nonlinear control or natural variables control, is based on a use of properly selected scalar variables in control feedback to linearize controlled system....
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Problems of Connecting Wind Farms to the Power System with HV Cables
PublicationThis paper presents problems caused by connecting wind farms to a power system with high voltage cables. The author highlights possible problems with reactive power compensation, depending on the arrangement of the shunt reactor connection and settings of control systems for reactive power and voltage of the wind farm. The paper also discusses issues of increasing active power losses caused by a shunt reactor installation.
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Kinetic analysis of the stage for a high speed steam turbine
PublicationThis article analyzes possibilites of resonances within a control stage for a high speed steam turbine. This stage hase been based on assembling of a single blade to a rotating disk and increasing of rigidity of the system by using of a bandage. In the analysis will be nd a possiblity of resonance frequency, and mistuning by showing safety working ranges. The calculations have bean used the3D modal and harmonic analysis by the...
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Effect of the inclination angle of the condenser on the heat transfer coefficient value – experimental study
PublicationWhen considering problem of the condensation of the refrigerant in a flow inside channel, one needs to pay attention to the shape of its cross-section, the hydraulic diameter, the channel length as well as the orientation of the channel axis in space (horizontal, vertical, inclined). This paper presents an experimental study concerning the effect of the inclination angle of the condenser with a single coil pipe on the heat transfer...